• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.47-53
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• 2019

To improve an aerodynamic characteristic of the eVOTL aircraft, Korea Aerospace Research Institute (KARI) performed a validity test of the cross-rotating propeller technology. First, CFD analysis was carried out and an idea of the cross-rotating propeller to imply on a multi-copter confirmed with a commerce pitch control multi-copter that has two different blades, 0.11 and 0.21 m. After verifying the idea, a multi-copter with about 3 kg maximum take-off weight (MTOW) was custom designed to complete a ground test to measure thrust and noise. The test was performed with 15 and 22 in. propellers at the identical tip speed. The test results show that the 22 in. propeller with the cross-rotating technology required about 30 % less power and reduced 3~5 dB aerodynamic noise as compared to 15 in. propeller without cross-rotating.

• Journal of Aerospace System Engineering
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• v.15 no.2
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• pp.26-35
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• 2021

In this study, CFD analysis was conducted to compare the aerodynamic performance of the isolated propeller and pusher propeller, which is affected by the wake of wide fuselage. The moving reference frame (MRF) method was used for isolated propeller analysis, while the MRF and sliding mesh method were used sequentially for the pusher propeller to analyze the change in the aerodynamic characteristics based on the azimuth angle. Under the same torque condition, the thrust of the pusher propeller was greater than that of the isolated propeller. Thrust increment of the pusher propeller was mainly generated near the root of the blade where the fuselage wake was concentrated. The net efficiency of the pusher propeller was greater than or equal to that of the isolated propeller. Because of the flat fuselage shape, thrust and torque of the pusher propeller periodically changed with the rotation of the propeller.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.3
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• pp.53-60
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• 2003

A test stand was developed to measure static performance of a reciprocating engine on the ground, related to the small aircraft being developed by KARI. The test stand consists of an apparatus to install and operate a pusher-type propulsion system and a data acquisition system to process many performance parameters including engine torque and propeller thrust as well as monitoring of the engine operations. First, the performance data from the basic operation tests were compared with the original engine data so the capacity of the test stand was verified. Engine performance tests were carried out with various test conditions through three stages, and it was measured and analyzed that the manifold pressure, the torque, and the back pressure of the engine, and the static thrust of the propeller.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.65-72
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• 2012

Numerical simulations were performed to study the stall characteristics of turboprop aircraft. Stall characteristics were qualitatively investigated using the computational results of various configurations based on the combinations of propeller and high lift device. For the analysis of stall characteristics, three-dimensional Navier-Stokes solver with Spalart-Allmaras turbulence model was used and the relative motion between propeller and wing was simulated using sliding mesh technique. For the cruise configurations, major flow separation was occurred at the fuselage/wing fairing and the separation was reduced under propeller slipstream condition. For the high lift device configuration without propeller, major flow separation was occurred at the outboard side of nacelle. With rotating propeller, early stall onset due to low relative velocity and high effective angle of attack was observed on the outboard wing section. Regarding rotating direction of propeller, inboard-down direction was preferred due to the stall delay effect of propeller slipstream.

• Proceeding of EDISON Challenge
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• 2012.04a
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• pp.21-24
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• 2012

본 논문은 HPA(Human Powered Aircraft) 제작 계획서를 작성하기 위해 프로펠러에 사용하는 에어포일을 작년에 접하게 된 EDISON-CFD 분석을 이용하여 기존에 X-foil로 얻어진 날개 익형에 대한 양력계수와 항력계수, 양항비와 비교하였다. 프로펠러 허브로부터 거리에 따른 단면에 해당하는 레이놀즈 수, 마하수, 받음각, 시위길이를 고려하여 에어포일을 분석해 보았다. 그 결과를 통해 프로펠러 에어포일을 선정하는데 많은 도움이 되었다. EDISON-CFD 분석에 대해 좀 더 공부하는 계기가 되어 우리 팀이 앞으로 졸업논문을 쓰는데 많은 도움이 될 것이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.371-377
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• 2009

The propulsion system of turboprop has been rarely used in the large aircraft due to the limitation of the maximum velocity of the propeller, the power limitation by the reduction gear, etc. Recently, the demand on turboprop aircraft continues to increase because of economical efficiency and environmental factors. In this paper, turboprop propulsion system which is composed of a Pratt & Whitney 127F turboprop engine and a Hamilton Standard 568F propeller was modeled by using the Gasturb11 software. The result of the performance analysis on this propulsion system model showed that the propulsion system model was evaluated to have been successfully builded.

• Journal of Aerospace System Engineering
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• v.9 no.3
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• pp.47-58
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• 2015

An aircraft, its engine and propeller are certified in processes of design, production, and operation respectively. Type Certificate is issued if the aviation authority finds that the design of aircraft, engine, or propeller complies with applicable airworthiness standards and environmental standards. The ICAO (International Civil Aviation Organization) prescribes the international standards and recommended practices of type certification for the contracting states. The FAA (Federal Aviation Administration) and the EASA (European Aviation Safety Agency) established their regulations and procedures applicable to type certification. In this paper, we compared the differences among the ICAO, the FAA, and the EASA regulations, and on this comparison, we proposed the rulemaking items to improve type certification regulations in Korea.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.6
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• pp.455-462
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• 2017

In recent decades, many researchers have been struggling to developing the compound aircraft that is capable high speed and VTOL flight. And in recent years, multi-copters are very popular because of having advantages of VTOL and easy handling, but they are lack of doing long-range mission. Therefore, we presents simple aircraft architecture which is equipped fixed wing, multi propellers and no control surfaces. In this paper, we designed the attitude control for the compound aircraft prototype and measured the attitude control performance with flight test for validating prototype's performance. We analysed the attitude control test result comparing with similar size of a fixed wing aircraft. The performance was almost same as fixed wing aircraft.

• Journal of Aerospace System Engineering
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• v.16 no.6
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• pp.54-63
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• 2022

Recently, electric propulsion aircraft with various propeller mounting positions have been under construction. The position of the propeller relative to the wing can significantly affect the aerodynamic performance of the aircraft. Placing the propeller in front of the wing produces a complex swirl flow behind or around the propeller. The up/downwash induced by the swirl flow can alter the wing's local effective angle of attack, causing a change in the aerodynamic load distribution across the wing's spanwise direction. This study investigated the influence of the distance between a propeller and a wing on the aerodynamic loads on the wing. The swirl flow generated by the propeller was modelled using an actuator disk theory, and the wing's aerodynamics were analysed with the VSPAERO tool. Results of the study were compared to wind tunnel test data and established that both axial and spanwise distance between the propeller and the wing positively affect the wing's lift-to-drag ratio. Specifically, it was observed that the lift-to-drag ratio increases when the propeller is positioned higher than the wing.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.1
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• pp.104-117
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• 1999

The Composite materials has been used in the field of high technology industry because of high specific stiffness and high specific strength. Specially, the composite materials has been widely applied to the field of the aircraft and the transportation by the effectiveness of light weight due to low specific weight and reduction of the parts due to bonding, molding and so on. These advantages about the composite have led to study and apply in the transmission shaft for the aircraft and the drive shaft for the automobile. The composite material propeller shaft with the high vibrational stability was designed and analyzed. In order to verify the analysis, two types of experimental test which are the FFT analyzer with impact hammer and the rotational equipment were applied.